Field of the Invention
The invention generally relates to environmental sensors and more particularly to sensors utilized in hydro dams or other hydraulic structures to assess the forces encountered by fish passing through such dams and other structures and characterize complex flow field.
Background Information
Fish passing through hydroturbines or other hydraulic structures may be injured or killed when they are exposed to the severe hydraulic conditions found therein. Such conditions could include rapid and extreme pressure changes, shear stress and turbulence, strike by runner blades and cavitation. In building new dams and as existing turbines near the end of their operational life and are set to be replaced, new designs for runners and other portions of the turbine system are being considered. As part of this effort, in the Pacific Northwest and elsewhere, improved survival rates and reduced injury rates for fish passing through turbines are being considered as design parameters. To create these designs, data is needed to understand the environment through which the fish were required to pass.
Studies using live fish are useful for the evaluation of dams' biological performance, but are limited in that they cannot determine the specific hydraulic conditions or physical stresses experienced by the fish, the locations where deleterious conditions occur, or the specific causes of the biological response. To overcome this deficiency, various other sensor devices have been developed. These devices can be released independently or concurrently with live fish directly into operating turbines or other passage routes as a means of measuring hydraulic conditions such as pressure, acceleration, and rotation acting on a body in situ during downstream passage. These early devices were originally designed for the large Kaplan turbines in the Columbia River basin and were used by the U.S. Army Corps of Engineers, who collaborated with the U.S. Department of Energy for its development, for virtually all of their post-construction structural and operations fish passage evaluations at main-stem Columbia River dams. Correlation metrics between these early sensor measurements and live fish injuries were also developed by conducting concurrent releases in turbulent shear flows under controlled laboratory conditions.
While useful in their time, these types of devices have tended to lack the sufficient robustness required to survive the rapidly changing and extreme conditions within the testing sites. In addition the speed at which conditions change made most of these sensors less useful because they were not able to acquire information in rapid fashion so as to give the true account of the significant changes that took place in the bodies of these fish as they passed through these environments. The size, functional limitations and problems with deployment and recovery, availability, and cost of these prior art devices have limited its use beyond the main stem Columbia River and its original application. As newer designs for turbines, dams, and pumping stations provide new and unknown conditions that the existing sensor devices cannot tolerate and which may not adequately reflect and report the conditions to which it is subjected.
Desirable devices overcome some of these limitations; they can be robust, cost accessible, as well as provide rapid data acquisition and be more widely deployable and be operable in more severe hydraulic conditions including but not limited to high-head dams with Francis turbines and pump storage facilities. Additionally, desirable devices can have outputs that can be more readily read and understood than the existing processes for the old devices.
The present disclosure provides sensor fish with more capabilities that can accelerate conventional hydropower development by shortening schedules and decreasing costs for validation of performance claims to regulators, and by providing feedback to design engineers about many of the hydro-turbine designs and environmental settings being considered to increase power generation. The sensor fish and utilization thereof can, lower the procurement and deployment costs which can be important for increasing the accessibility and acceptance of this sensing technology.
Additional advantages and novel features of the new sensor fish and methods will be set forth as follows and will be readily apparent from the descriptions and demonstrations set forth herein. Accordingly, the following descriptions of the present fish and methods should be seen as illustrative of the fish and methods and not as limiting in any way.